Metaproteomic Insights Into the Microbial Community in Pozol
Jocelin Rizo1,2, Daniel Guillén1, Gloria Díaz-Ruiz3
1Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico.
Abstract:
Pozol is an acidic, refreshing, and non-alcoholic traditional Mayan beverage made with nixtamalized corn dough that is fermented spontaneously. The extensive analysis of the microbiology, biochemistry and metaproteomics of pozol allowed the construction of a comprehensive image of the fermentation system. The main changes in both the substrate and the microbiota occurred in the first 9 h of fermentation. The increase in microorganisms correlated with the drop in pH and with the decrease in the contents of carbohydrates, lipids, and nitrogen, which shows that this stage has the highest metabolic activity. Bacterial proteins were mainly represented by those of lactic acid bacteria, and among them, the proteins from genus Streptococcus was overwhelmingly the most abundant. Yeast proteins were present in all the analyzed samples, while proteins from filamentous fungi increased up to 48 h. The metaproteomic approach allowed us to identify several previously unknown enzyme complexes in the system. Additionally, enzymes for hydrolysis of starch, hemicellulose and cellulose were found, indicating that all these substrates can be used as a carbon source by the microbiota. Finally, enzymes related to the production of essential intermediates involved in the synthesis of organic acids, acetoin, butanediol, fatty acids and amino acids important for the generation of compounds that contribute to the sensorial quality of pozol, were found.
Insights
This study reveals the complex microbial and biochemical changes during pozol fermentation, a traditional Mayan beverage. Key findings highlight the crucial role of lactic acid bacteria and enzyme activity in developing pozol's unique characteristics.
Area of Science:
- Food Science and Technology
- Microbiology
- Biochemistry
Background:
- Pozol is a traditional, non-alcoholic Mayan beverage fermented from nixtamalized corn dough.
- Spontaneous fermentation leads to a complex microbial ecosystem within pozol.
Purpose of the Study:
- To comprehensively analyze the microbiology, biochemistry, and metaproteomics of pozol fermentation.
- To understand the dynamic changes in substrate and microbial composition during fermentation.
Main Methods:
- Microbiological analysis to identify microbial populations.
- Biochemical assays to measure changes in pH, carbohydrates, lipids, and nitrogen.
- Metaproteomic analysis to identify key proteins and enzyme complexes.
Main Results:
- Significant microbial and biochemical changes occurred within the first 9 hours of fermentation.
- Lactic acid bacteria, particularly *Streptococcus*, dominated bacterial protein profiles.
- Enzymes involved in starch, hemicellulose, and cellulose hydrolysis were identified, alongside those producing flavor compounds.
Conclusions:
- The early stages of fermentation are critical for pozol's metabolic activity and characteristic profile.
- Metaproteomics revealed novel enzyme complexes and confirmed the utilization of diverse carbon sources.
- The identified enzymes contribute to the production of acids, acetoin, butanediol, fatty acids, and amino acids, enhancing pozol's sensory qualities.
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